title: Appearance and impact of post-operative intracranial clips and coils on whole-brain CT angiography and perfusion.
abstract: BACKGROUND
  To evaluate the effect of vascular clips and endovascular coils placed for intracranial aneurysms and arteriovenous malformations on whole-brain computed tomography (CT) angiography and perfusion.
  
  
  METHODS
  A 320-detector row dynamic volume CT system imaged 11 patients following surgical placement of vascular clips or endovascular coils. The extent of clip and coil subtraction by automated software was evaluated using CT digital subtraction angiography and CT perfusion. Impact on CT perfusion values by retained intracranial devices was compared to age- and gender-matched controls.
  
  
  RESULTS
  Clip and coil subtraction on CT angiography was graded as good in 8 and moderate in 3 cases. A residual neck and additional aneurysm were noted in 1 of 11 patients. Post-procedural axial slice level CT perfusion values decreased in reliability with increasing proximity to the metallic devices secondary to beam hardening. However, the intracranial devices did not affect axial slice level CTP values of cerebral blood volume, cerebral blood flow and mean transit time outside of the level of the device. Time to peak values was globally decreased outside of the immediate vascular intervention region.
  
  
  CONCLUSIONS
  Advances in CT technology have provided clinically useful subtraction of intracranial clips and coils. While CT perfusion values were altered in device subtraction areas and within beam hardening artifact areas; they can provide valuable postoperative information on whole-brain hemodynamics. In selected cases, the combination of CT angiography and whole-brain CT perfusion can offer an alternative to conventional angiography that is a more invasive option.
authors.affiliation: Advanced Medical Imaging and Genetics (Amigenics), 5495 South Rainbow Boulevard, Suite 201, Las Vegas, NV 89118, USA. caycer@gmail.com
authors.forename: Cayce J
authors.initials: CJ
authors.lastname: Roach
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Russell
authors.forename: Eric H
authors.initials: EH
authors.lastname: Hanson
authors.forename: Brent
authors.initials: B
authors.lastname: Bluett
authors.forename: William W
authors.initials: WW
authors.lastname: Orrison
mesh_terms: D002533:Cerebral Angiography / Q000379:methods*; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome